When a guard discovers an unusual lifeform on her remote moon outpost, she disregards protocol to investigate―with catastrophic consequences. It soon becomes clear she's stuck in isolation with an alien capable of incredible depravity. The parasite wears its victims' skins and adopts their personalities. It mimics the way they talk, the way they look, the way they act. It's the perfect disguise.

And by the time humanity realizes it's facing extinction, it's already too late.

As the alien's ruthless progress collapses communication networks, wipes out defenses, and leaves hundreds of stations to fend for themselves, a handful of remarkable individuals must find a way to battle the greatest threat the universe has ever encountered... or die trying.